If you're suffering from knee pain in the middle of the night, you're not alone. Any number of medical conditions can become aggravated during the nighttime hours and cause you pain while you're trying to sleep.
A common form of knee and leg pain that can get worse during the night is osteonecrosis, which means bone death. Women are more likely than men to be afflicted by this condition, which is the result of a bone losing its blood supply and beginning to die. The knobby portion of the thighbone on the inside of the knee is the main target of osteonecrosis, but it can occur on the outside of the knee. You will feel increased pain at night and when you are active.
Rheumatoid arthritis (RA) can affect the joints in your legs, knees and hip. Pain and swelling result. You may not be able to rest comfortably at night because of the pain. When you awaken, you will most likely be achy and stiff.
If you have osteoarthritis--the degenerative kind of arthritis that generally afflicts older people--you may be roused from sleep because of knee pain, particularly if you have overused your joints the previous day. Weather conditions, including barometric pressure changes, can exacerbate arthritic pain. If the weather changes during the night, you may be the first to know.
If you have injured a ligament, a tendon or one of the fluid-filled sacs (bursae) that surround your knee joint, this can cause pain, at night as well as in the day.
Gout, which is a form of arthritis, may produce intense pain at night that comes on suddenly. Redness and swelling will occur, according to the Mayo Clinic.